Fiber optic articles, such as for example, optical fiber preforms or optical fibers, can advantageously include one or more materials, such as, for example, one or more rare earths. The fiber can also include one or more other materials that can enhance the performance of the article, such as by reducing clustering or concentration quenching of the rare earths. Rare earths can be useful in lasers, amplifiers, superfluorescent sources, amplified spontaneous emission (ASE) sources and the like, as they can, in most instances, provide light having a selected wavelength responsive to the article receiving light (e.g., being “pumped” by “pump” light) having a different wavelength. Additionally or alternatively, one or more rare earths can be selected to absorb light.
Unfortunately, an optical article comprising one or more materials in the combinations or concentrations required to achieve a desired performance according to a first criterion can result in performance characteristic according to another criterion that is outside a desired range. For example, concentrations of materials desirable in a laser or amplifier to promote efficiency can result in an optical waveguide core having a higher numerical aperture than desired, as most materials known to be added to promote efficiency also raise the index of refraction of the host material (e.g., silica glass) that includes the materials.
It is an object of the present invention to address one or more of the deficiencies or disadvantages of the prior art.